# Relationship history for MSHA mine 0400899

Current hierarchy: **Avocet Mining Plc → Avocet Tungsten Inc → PINE CREEK MINE**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Umetco Minerals Corp → PINE CREEK MINE; 1950-01-01 to 1986-06-23; source msha-controller-operator-history
- **controller_controls_mine:** Union Carbide Corp → PINE CREEK MINE; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Union Carbide Corp → Umetco Minerals Corp; 1950-01-01 to 1986-06-23; source msha-controller-operator-history
- **operator_operates_mine:** U S Tungsten Corp → PINE CREEK MINE; 1986-06-24 to 1998-08-10; source msha-controller-operator-history
- **controller_controls_mine:** Strategic Minerals Corp (Stratcor) → PINE CREEK MINE; 1986-06-24 to 1998-08-10; source msha-controller-operator-history
- **controller_controls_operator:** Strategic Minerals Corp (Stratcor) → U S Tungsten Corp; 1986-06-24 to 1998-08-10; source msha-controller-operator-history
- **controller_controls_mine:** Avocet Mining Plc → PINE CREEK MINE; 1996-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Avocet Tungsten Inc → PINE CREEK MINE; 1998-08-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Avocet Mining Plc → Avocet Tungsten Inc; 1998-08-11 to current/open; source msha-controller-operator-history